In many printers, individual sheets of paper or other print media are fed into the printer off the top of a stack of sheets held in a tray. Typically, a pick roller is rotated against the top sheet to slide the top sheet off the stack and into a set of rollers that feed the sheet into the print engine. The friction between sheets in the stack sometimes causes the top two or three sheets in the stack to stick together as the top sheet is picked from the stack. The next-to-top sheets must be separated from the top sheet to avoid feeding multiple sheets into the print engine at the same time.
In one conventional input structure, the next-to-top sheets are separated from the top sheet by driving the sheets against an angled wall positioned at the front of the media input tray. This separation wall also functions as a load stop to prevent the user from pushing media too far into the printer when a media stack is loaded into the tray. Since the wall is angled, however, it is comparatively easy for the user to push the stack partially up the separation wall and too far into the printer, which prevents effective sheet separation.
In some printers, an elastomeric pad is embedded in the separation wall to make it more difficult for a user to load the media stack too far into the printer. The compressibility and high surface friction of the pad create a desirable increase in the resistance to the media stack during loading. Unfortunately, a uniform pad that creates enough resistance to function as an effective load stop can also create too much resistance to the top sheet picked from the stack and pushed up the separation wall along the pad.